Pattern forming systems coupling linear bulk diffusion to dynamically active membranes or cells

Some analytical and numerical results are presented for pattern formation properties associated with novel types of reaction–diffusion (RD) systems that involve the coupling of bulk diffusion in the interior of a multi-dimensional spatial domain to nonlinear processes that occur either on the domain boundary or within localized compartments that are confined within the domain. The class of bulk-membrane system considered herein is derived from an asymptotic analysis in the limit of small thickness of a thin domain that surrounds the bulk medium. When the bulk domain is a two-dimensional disk, a weakly nonlinear analysis is used to characterize Turing and Hopf bifurcations that can arise from the linearization around a radially symmetric, but spatially non-uniform, steady-state of the bulk-membrane system. In a singularly perturbed limit, the existence and linear stability of localized membrane-bound spike patterns is analysed for a Gierer–Meinhardt activator-inhibitor model that includes bulk coupling. Finally, the emergence of collective intracellular oscillations is studied for a class of PDE-ODE bulk-cell model in a bounded two-dimensional domain that contains spatially localized, but dynamically active, circular cells that are coupled through a linear bulk diffusion field. Applications of such coupled bulk-membrane or bulk-cell systems to some biological systems are outlined, and some open problems in this area are discussed. This article is part of the theme issue ‘Recent progress and open frontiers in Turing’s theory of morphogenesis’.

Comparison of hydrodynamic and acoustic pressure on automotive front side window

The unsteady flow in the front side window region of the vehicle can generate hydrodynamic and acoustic pressure on the front side window, which can influence the interior sound field. The hydrodynamic pressure on the front side window was achieved by the incompressible wall-modeled large-scale eddy simulation (WMLES) or improved delayed detached eddy simulation (IDDES), and the hybrid computational aeroacoustics (CAA) method based on acoustic perturbation equations (APE) was employed to achieve the acoustic pressure on the front side window. The numerical results of both hydrodynamic and acoustic pressure ware validated by the wind tunnel experiment, especially the corrected force analysis technique (CFAT) is employed to validate the acoustic pressure. The comparison of hydrodynamic and acoustic pressure on the front side window was performed by the Dynamic Mode Decomposition (DMD). Results show that the hydrodynamic pressure regionally distributes on the front side window and most energy concentrates on area interacted with the side mirror wake, while the acoustic pressure distributes uniformly on the front side window acting as a diffusion field and the energy disperses in frequency region.

Chemical-diffusion Metamaterials with “Plug and Switch” Modules for Ion Cloaking, Concentrating and Selection: Design and Experiments

The outstanding abilities of metamaterials to manipulate physical fields have been extensively studied in wave-based fields. Recently, this research has been extended to diffusion fields. Chemical diffusion behavior is crucial in a wide range of fields including the transportation of various matters, and metamaterials with the ability to manipulate diffusion with practical applications associated with chemical and biochemical engineering have not yet been proposed. In this work, we propose the idea of a “plug and switch” metamaterial to achieve the switchable functions of ion cloaking, concentrating and selection in liquid solvents by plugging modularized functional units into a functional motherboard. The respective modules are theoretically designed based on scattering cancellation, and the properties are verified by both simulations and experiments. Plugging in any module barely affects the environmental diffusion field, but the module choice impacts different diffusion behaviors in the central region. Cloaking strictly hinds ion diffusion, and concentrating promotes a large diffusion flux, while cytomembrane-like ion selection permits the entrance of some ions but blocks others. In addition to property characterization, these functions are demonstrated in special applications. The concentrating function is experimentally verified by catalytic enhancement, and the ion selection function is verified by protein protection. This work not only demonstrates the effective manipulation of metamaterials in terms of chemical diffusion behavior but also shows that the "plug and switch" design is extensible and multifunctional, and facilitates novel applications including sustained drug release, catalytic enhancement, bioinspired cytomembranes, etc.

Characterization and eradication of the high concentration infection source of oral segment of Candida by infection examination diagnosis system

Purpose: Candida albicans (CA) is a major pathogenic fungus that causes a critical infection and life-threatening disease. Currently, during the treatment of COVID-19 (in ICU), invasive Candidiasis and Candida colonization should be prevented to avoid the increase, in mortality, in SAPSII, and in length of stay. Our aim was to characterize and analyze the infection of CA for eradication. Methods: We characterized and analyzed the infection source and infection field which are carrier field, diffusion field, and spread field, by using a new infection examination (diagnostic) system (IEDS) comprising a new dental formula (measurement analysis) medium (DFM) with time, space, and phase, and the simultaneous relative differential equations (C4RDE). Results: This study showed that CA was not an endogenous microorganism, but a fungus that infected teeth causing dental caries that was successfully eradicated from all teeth of 353 Japanese patients. Conclusion: Our methods help to eradicate the infection source, prevent critical infection, and reduce mortality. The IEDS is a powerful tool that can be applied for any infection easily. It is possible for the dentists to characterize CA by IEDS and eradicate CA from the oral cavity. IE(D)S will dramatically reduce the threat to the living body by pathogenic microorganisms.

Characterization and eradication of the high concentration infection source of oral segment of Candida by infection examination diagnosis system

Purpose: Candida albicans (CA) is a major pathogenic fungus that causes a critical infection and life-threatening disease. Currently, during the treatment of COVID-19 (in ICU), invasive Candidiasis and Candida colonization should be prevented to avoid the increase, in mortality, in SAPSII, and in length of stay. Our aim was to characterize and analyze the infection of Candida albicans (CA) for eradication. Methods: We characterized and analyzed the infection source and infection field which are carrier field, diffusion field, and spread field, by using a new infection examination (diagnostic) system (IEDS) comprising a new dental formula (measurement analysis) medium (DFM) with time, space, and phase, and the simultaneous relative differential equations (C4RDE).Results: This study showed that CA was not an endogenous microorganism, but a fungus that infected teeth causing dental caries that was successfully eradicated from all teeth of 353 Japanese patients (oral cavity segment). [In the first examination, the percentages of people with CA (+) was 40.5% (the DMFT: 62.8%) and CA(-) was 56.4% (the DMFT: 47.1%). The difference in DMFT was 15.7% (P<0.01)] (DMFT is decayed, missing, and filled tooth index).Conclusion: Eradication of the infection source (IS) of the oral segment(s) and breaking the infection chain (IC) by IE(D)S will dramatically reduce the threat to the living body by pathogenic microorganisms. And, our methods help to eradicate the infection source (IS), prevent critical infection, and reduce mortality. The IEDS is a powerful tool that can be applied for any microbial infection easily. It is possible for the dentists to characterize CA by IEDS and eradicate CA from the oral cavity. Moreover, CA must consider the phase of the space-time of infection source, infection field, receptor field, resistance field, adhesive colony, fixed colony and infection chain. Moreover, CA must consider the phase of microorganisms. If they are neglected, the statistical research or the medical treatment etc., the study cannot obtain the correct result.

Characterization and Eradication of The High Concentration Infection Source of Oral Segment of Candida By Infection Examination Diagnosis System

Purpose: Candida albicans (CA) is a major pathogenic fungus that causes a critical infection and life-threatening disease. During ventilator usage for the treatment of COVID-19-associated pneumonia, CA colonization of the airway should be prevented to avoid an increase in mortality. Our aim was to characterize and analyze the infection of Candida albicans (CA) for eradication.Methods: We characterized and analyzed the infection source and infection field which are carrier field, diffusion field, and spread field, by using a new infection examination (diagnostic) system (IEDS) comprising a new dental formula (measurement analysis) medium (DFM) with time, space, and phase, and the simultaneous relative differential equations (C4RDE).Results: This study showed that CA was not an endogenous microorganism, but a fungus that infected teeth causing dental caries that was successfully eradicated from all teeth of 353 Japanese patients (oral cavity segment). [In the first examination, the percentages of people with CA (+) was 40.5% (the DMFT: 62.8%) and CA(-) was 56.4% (the DMFT: 47.1%). The difference in DMFT was 15.7% (P<0.01)] (DMFT is decayed, missing, and filled tooth index).Conclusion: Our methods help to eradicate the infection source (IS), prevent critical infection, and reduce mortality. The IEDS is a powerful tool that can be applied for any microbial infection easily. It is possible for the dentists to characterize CA by IEDS and eradicate CA from the oral cavity.

Analysis of the Dependence of the Apparent Sound Reduction Index on Excitation Noise Parameters

In acoustic practice, established methods of measuring the acoustic properties of partition structures are used. Recommended procedures and means can be found in technical standards, but practice suggests that measurement results may also depend on measurement conditions. These procedures leave the choice of noise type, frequency interval examined, and excitation interval on the measurer. The aim of this research is to determine which parameter has a significant effect on the results, and to quantify the extent of this effect. We examined the type of noise, the frequency band of the sound passing through the partition structure and the excitation interval of the diffusion field in the rooms (hereinafter referred to as “excitation interval”). During the research, we conducted a number of repeated, statistically significant measurements, which we first evaluated by classical methods used in acoustic practice. We subjected the obtained results to a thorough mathematical analysis. Evaluation of the results shows that some measurement conditions significantly affect the resulting values, especially in the low-frequency spectrum. One of the most important elements which has an effect on the results is the type of excitation noise, which, when assessed in the source room, excites the diffuse sound field, and its transmission through the considered partition structure is measured. The significance of the investigated frequency interval was also demonstrated.

Photoinduced light scattering and photoelectric fields in zinc doped lithium niobate crystals.

Nominally pure and doped with zinc in a wide concentration range lithium niobate crystals were studied using photoinduced light scattering. Using the parameters of photo-induced scattered light, we determined the values of the photovoltaic and diffusion field intensities in lithium niobate crystals of different compositions. It was found that the values of thephotoelectric field strengths depend on the state of the defect structure of the crystals.

Geodesic Loewner paths with varying boundary conditions

Equations of the Loewner class subject to non-constant boundary conditions along the real axis are formulated and solved giving the geodesic paths of slits growing in the upper half complex plane. The problem is motivated by Laplacian growth in which the slits represent thin fingers growing in a diffusion field. A single finger follows a curved path determined by the forcing function appearing in Loewner’s equation. This function is found by solving an ordinary differential equation whose terms depend on curvature properties of the streamlines of the diffusive field in the conformally mapped ‘mathematical’ plane. The effect of boundary conditions specifying either piecewise constant values of the field variable along the real axis, or a dipole placed on the real axis, reveal a range of behaviours for the growing slit. These include regions along the real axis from which no slit growth is possible, regions where paths grow to infinity, or regions where paths curve back toward the real axis terminating in finite time. Symmetric pairs of paths subject to the piecewise constant boundary condition along the real axis are also computed, demonstrating that paths which grow to infinity evolve asymptotically toward an angle of bifurcation of π /5.